[FONT=Arial,Helvetica]TurboMMU040+ 1.0 ©SpeedGeek 2018
INTRODUCTION:
TurboMMU040+ is an MMU tool to maximize the MMU performance of
most* 68040 and 68060 libraries. The MMU is a most excellent
and valuable feature of advanced 68K CPUs. Unfortunately, it's
usage does not come without any performance loss. How much
performance is lost depends on many factors, but this tool
deals specifically with the MMU configuration factors.
FEATURES:
- Enables 8K page mode MMU operation!
- Converts existing 4K page tables to 8K page tables
- Does NOT increase memory usage for MMU tables
- Enables (optional) ITTx management for 32GB of address
space!
- Uses 68040/060 library detection code
- 100% Assembler code
REQUIREMENTS:
- Amiga with 68040 or 68060 CPU and MMU
- 68040.library or 68060.library
PERFORMANCE AND TECHNICAL ISSUES:
The 8K page size provides a 2x increase in the address space
which resides in the ATC. When a page address "Hits" in the
ATC it provides a "Zero" wait state address translation.
When a page address "Misses" in the ATC the MMU performs a
table search in memory to find the page address. Hence, many
wait states are incurred which result in a performance loss.
Both the 68040 and 68060 have a 64 entry ATC so 64 x 4K = 256K
and 64 x 8K = 512K.
The ITTx registers manage the instruction page descriptors
for a 16MB - 32GB size of address space. They are typically
disabled but may be enabled for part of the address space by a
few libraries. TurboMMU040 optionally enables it for the full
32GB of address space. This effectively bypasses the MMU
and provides "Zero" wait state performance for all instruction
translations. The ITTx usage trade off is the loss of the of
the performance benefit (if any) from remapping the Kickstart
ROM(s) into Fast memory. Also, if the library has already
enabled the ITTx you may want to keep the default settings.
WARNINGS:
Failure to disable or unmap MMU remapped Kickstart ROM(s)
will result in a loss of memory which can NOT be reclaimed
after conversion to 8K pages (YOU HAVE BEEN WARNED!).
Attempted usage of this tool with existing 4K MMU tools is
VERY risky! Some tools will check the page size and safely
exit, but others will just assume the page size is correct
and proceed to crash your system! Likewise, libraries which
have a built in API (e.g. Phase 5) should be used with
caution.
This tool does NOT always provide an identical memory map to
the original. Specific cases when mapping will change are:
1) MMU remapping of the Zero page area is disabled.
2) SRP table differs from URP table (URP table replaces SRP
table).
3) The Kickstart MMU remap warnings have been ignored (All
physical ROM addresses are restored).
*Compatibility support for most 68040 and 68060 libraries does
NOT mean all of them!
NOTES:
The executable file name excludes the "+" character to avoid
problems with the Amiga Shell. See TurboMMUtools.txt for info
on the initial support tools.
HISTORY:
v1.0 - First release
Here is the link:
http://eab.abime.net/showthread.php?p=128823[/FONT]
INTRODUCTION:
TurboMMU040+ is an MMU tool to maximize the MMU performance of
most* 68040 and 68060 libraries. The MMU is a most excellent
and valuable feature of advanced 68K CPUs. Unfortunately, it's
usage does not come without any performance loss. How much
performance is lost depends on many factors, but this tool
deals specifically with the MMU configuration factors.
FEATURES:
- Enables 8K page mode MMU operation!
- Converts existing 4K page tables to 8K page tables
- Does NOT increase memory usage for MMU tables
- Enables (optional) ITTx management for 32GB of address
space!
- Uses 68040/060 library detection code
- 100% Assembler code
REQUIREMENTS:
- Amiga with 68040 or 68060 CPU and MMU
- 68040.library or 68060.library
PERFORMANCE AND TECHNICAL ISSUES:
The 8K page size provides a 2x increase in the address space
which resides in the ATC. When a page address "Hits" in the
ATC it provides a "Zero" wait state address translation.
When a page address "Misses" in the ATC the MMU performs a
table search in memory to find the page address. Hence, many
wait states are incurred which result in a performance loss.
Both the 68040 and 68060 have a 64 entry ATC so 64 x 4K = 256K
and 64 x 8K = 512K.
The ITTx registers manage the instruction page descriptors
for a 16MB - 32GB size of address space. They are typically
disabled but may be enabled for part of the address space by a
few libraries. TurboMMU040 optionally enables it for the full
32GB of address space. This effectively bypasses the MMU
and provides "Zero" wait state performance for all instruction
translations. The ITTx usage trade off is the loss of the of
the performance benefit (if any) from remapping the Kickstart
ROM(s) into Fast memory. Also, if the library has already
enabled the ITTx you may want to keep the default settings.
WARNINGS:
Failure to disable or unmap MMU remapped Kickstart ROM(s)
will result in a loss of memory which can NOT be reclaimed
after conversion to 8K pages (YOU HAVE BEEN WARNED!).
Attempted usage of this tool with existing 4K MMU tools is
VERY risky! Some tools will check the page size and safely
exit, but others will just assume the page size is correct
and proceed to crash your system! Likewise, libraries which
have a built in API (e.g. Phase 5) should be used with
caution.
This tool does NOT always provide an identical memory map to
the original. Specific cases when mapping will change are:
1) MMU remapping of the Zero page area is disabled.
2) SRP table differs from URP table (URP table replaces SRP
table).
3) The Kickstart MMU remap warnings have been ignored (All
physical ROM addresses are restored).
*Compatibility support for most 68040 and 68060 libraries does
NOT mean all of them!
NOTES:
The executable file name excludes the "+" character to avoid
problems with the Amiga Shell. See TurboMMUtools.txt for info
on the initial support tools.
HISTORY:
v1.0 - First release
Here is the link:
http://eab.abime.net/showthread.php?p=128823[/FONT]